Rebels are sus­pected in a wave of vi­o­lence, in­clud­ing am­bushes and oil spills, amid peace ne­go­ti­a­tions.

PUERTO ASIS, Colom­bia — Al­ready stag­nant peace talks be­tween the Colom­bian gov­ern­ment and left­ist rebels have been thrown fur­ther into ques­tion by a score of at­tacks by in­sur­gents on mostly civil­ian tar­gets over the last week.

The vi­o­lence has “struck at Colom­bians’ con­fi­dence in the process,” Pres­i­dent Juan Manuel San­tos said.

The week of vi­o­lence by sus­pected rebels of the Rev­o­lu­tion­ary Armed Forces of Colom­bia, or FARC, was di­rected at oil pipe­lines and in­fra­struc­ture in par­tic­u­lar. There also were nu­mer­ous at­tacks on high-volt­age elec­tri­cal tow­ers, leav­ing an es­ti­mated 1 mil­lion peo­ple in the cities of Bue­naven­tura, Tu­maco and Floren­cia tem­po­rar­ily with­out power.

On Fri­day, a dis­trict com­man­der of the Colom­bian Na­tional Po­lice was killed along with a pa­trol­man af­ter their ve­hi­cle was am­bushed in the south­ern state of Narino. Col. Al­fredo Clav­ijo of the Ipi­ales dis­trict was shot at close range, po­lice com­man­der Gen. Rodolfo Palomino said.

San­tos — in video­taped com­ments re­leased Satur­day to re­porters in Rome, a stop on an ex­tended trip de­signed in part to so­licit post­con­flict eco­nomic aid from Euro­pean coun­tries — de­scribed the at­tacks as “sense­less” but vowed to push ahead with the peace talks, which be­gan in Ha­vana in Novem­ber 2012.

“When we be­gan talks with the FARC more than 21⁄ years ago, we agreed we would ne­go­ti­ate amid the con­flict and I traced some red lines that we would not cross,” San­tos said. “We shouldn’t for­get that one of those red lines is that we would talk amid the conf lict.”

The at­tacks were es­pe­cially felt in this south­ern Colom­bian re­gion where sus­pected rebels, in two sep­a­rate in­ci­dents, forced driv­ers of 22 tanker trucks to dis­gorge their loads of crude oil on ru­ral road­ways, pol­lut­ing pas­tures and a stream that feeds into the Pu­tu­mayo River, which emp­ties into the Ama­zon.

Res­i­dents in Pu­tu­mayo prov­ince said the at­tacks will only ag­gra­vate eco­nomic woes caused by a re­cent down­turn in the price of crude oil, which in turn has forced the shut­ting of wells, lay­offs of hun­dreds of oil field work­ers and the idling of dozens of tanker trucks.

The at­tacks will make oil com­pa­nies even more re­luc­tant to op­er­ate and will harm the liveli­hoods of poor work­ers, trans­port owner Lu­ciano Tello said. “Be­fore, we had all kinds of busi­ness shut­tling driv­ers. So did restau­rants and ho­tels in the city. Boys found work at the wells eas­ily. But it’s dried up,” Tello said.

Nora Dominguez, owner of a road­side cafe east of Puerto Asis and less than a mile from where rebels on Thurs­day forced three tanker trucks to dis­charge their loads on a gravel road, said only four or five trucks pass each day, down from 25 or 30 a year ago. “It’s re­ally quiet now and it will get worse,” she said.

Mean­while, a spokesman for the state-con­trolled oil com­pany Ecopetrol said the com­pany was still try­ing to keep a spill caused by the June 8 bomb­ing of the Transandino Pipe­line from en­ter­ing the Pa­cific Ocean at the port city of Tu­maco. The spill di­verted up to 170,000 gal­lons of crude into a stream that emp­ties into the Rosario River.

The new wave of rebel vi­o­lence is the most se­ri­ous since peace talks started in 2012 to end the 50-year-old conf lict, the hemi­sphere’s long­est-run­ning war. It was also the first co­or­di­nated se­ries of at­tacks since the rebels called off their five­month cease-fire on May 22.

The FARC’s mo­tive is thought to be a show of strength to force the gov­ern- ment to agree to a bi­lat­eral cease-fire, which the San­tos ad­min­is­tra­tion has re­fused to do un­til an over­all peace agree­ment has been signed, said Bruce Ba­gley, a Colom­bia spe­cial­ist at the Uni­ver­sity of Miami.

“Pres­i­dent San­tos has taken the high road in in­sist­ing that the talks must con­tinue de­spite the re­cent es­ca­la­tion of vi­o­lence un­til a fi­nal ac­cord is reached,” said Vir­ginia Bou­vier of the United States In­sti­tute of Peace. But “the FARC has made a mis­cal­cu­la­tion. With more vi­o­lence they will not gain ground at the ne­go­ti­at­ing ta­ble, and they can prej­u­dice the prospects for the rat­i­fi­ca­tion of any fi­nal agree­ment they might pro­duce.”

Adam Isac­son, a Colom­bia re­searcher at the Wash­ing­ton Of­fice on Latin Amer­ica, a think tank in Wash­ing­ton, said that de­spite the surge in vi­o­lence, the odds are good that the peace talks will con­tinue, not­ing that slow but in­cre­men­tal progress has been made. But the fu­ture hinges on whether the at­tacks con­tinue.

“It’s a bump in the road if the at­tacks stop this week, but if it’s a sus­tained of­fen­sive, it will make Colom­bians even more an­gry and force the San­tos gov­ern­ment to get up from the ta­ble and sus­pend the process,” Isac­son said. “The dan­ger in a sus­pen­sion is it could be­come per­ma­nent.”

French so­ci­ol­o­gist and Colom­bia ex­pert Daniel Pe­caut, who has ad­vised the San­tos gov­ern­ment in the ne­go­ti­a­tions, said he doubts that at this stage any po­lit­i­cal fac­tion in Colom­bia re­ally wants the talks to end, be­cause it would con­sti­tute a “leap into the un­known.”

Although the ne­go­ti­a­tions have pro­duced ten­ta­tive agree­ments on three of five ma­jor points and, more re­cently, joint co­op­er­a­tion in de-min­ing and the for­ma­tion of a truth com­mis­sion, the two sides have been at a stand­off since May 2014 on the is­sue of “tran­si­tional jus­tice.”

That’s the broad term for the post-conf lict is­sue of whether FARC com­man­ders will stand trial and serve pri­son time for crimes against hu­man­ity, a prospect the rebels re­ject. Poll re­sults pub­lished in early May in Se­m­ana mag­a­zine in­di­cated that 89% of Colom­bians be­lieve FARC lead­ers should do time if con­victed of such crimes, an im­por­tant in­di­ca­tor be­cause any fi­nal peace deal will be sub­mit­ted to a na­tional vote.

“Sup­pos­ing that a deal is ar­rived at one day in Ha­vana, how will the ref­er­en­dum go given the grow­ing ha­tred to­ward the FARC?” Pe­caut said.

Chris Kraul
For The Times

A POND that cat­tle drank from was pol­luted by crude oil af­ter at­tack­ers forced tanker truck driv­ers to dump their loads on a road near Puerto Asis, Colom­bia. An­a­lysts said the vi­o­lence may back­fire on the rebels.